(a) Field of the Invention
This invention relates to a device used for measuring and analyzing colors and more particularly, but not by way of limitation, to a handheld, portable color measuring device adapted for use with and without a personal computer and used for measuring colors of various objects.
(b) Discussion of Prior Art
Heretofore in many color measuring applications, there is a continuous need to analytically measure a color of an object, to compare colors of different materials or compare objects with each other and to reference a color standard. For example, matching an injection molded product to a customer""s color reference standard or matching paint to a paint manufacturer""s paint swatch.
There are many industries where there are benefits to having an analytical means to measure color. For example, on today""s market there are color measurement devices which can analytically measure color, but they are generally very expensive. Also, these devices are complex in operation which limits the number of users. With the advent of new computer technologies related to portable personal computers, an accurate color measuring device, as disclosed herein, is now affordable and easily made portable.
U.S. Pat. No. 5,838,451 to McCarthy discloses a system for optoelectronic spectral analysis. The system uses an apparatus having multiple LEDs disposed around a photosensor. The photosensor and LEDs are mounted on a common substrate along with a lens for coupling light to and from a color target.
U.S. Pat. No. 5,844,680 to Sperling describes a device and process for measuring and analyzing spectral radiation. The device includes a wavelength spectra having multiple sources and sensors which overlap to provide a full spectrum color measurement within a color range of interest.
U.S. Pat. No. 5,691,701 to Wohlstein et al, discloses a fluid or vapor diagnostic device. The device uses multicolored LED""s for sensing a color of a gas or fluid. Also, the device uses fiber optics for coupling light from the gas, fluid or vapor.
U.S. Pat. Nos. 5,851,113 to Jung, et al. and 5,690,486 to Zigelbaum disclose two different types of apparatus and method for measuring the color of teeth. The two dental devices are used to determine the correct color of restorative dental material to use when repairing a damaged tooth.
U.S. Pat. No. 6,157,454 to Wagner et al. discloses a miniature colorimeter for taking color measurements of an object. The object is illuminated using a light pipe with a light source made up of red, green and blue LED""s. A light sensor senses the reflected light from the object. The light sensor is connected to a microprocessor and a display panel.
While the above systems and devices are used for various types of color spectral analysis, none of them specifically disclose the unique structural features, functions, objects and advantages of the subject handheld color measuring device.
In view of the foregoing, it is a primary objective of the subject invention to provide a unique color measuring device which is lightweight, handheld, inexpensive and portable.
Another object of the color measuring device can be a free standing unit including its own built in display. Also, the device can be connected to a personal computer such as a Compact Companion, a Palm Pocket PC, a Handspring Pocket PC and the like for storage data and providing a visual display.
Yet another object of the color measuring device is by using a LED white light source and a single 3 color sensor, percentages of red, green and blue and other multiple colors can be detected either simultaneously or sequentially. Also, the sensor includes color coating for more controllable and consistent wavelength output, thereby eliminating a need for notch filters.
A further object of the invention is the 3-color sensor is connected to an analog printed circuit board, which reduces transient noise levels by eliminating the use of cables from the sensor to the circuit board. This feature provides for a better signal to noise ratio thus enabling improved discrimination of colors in dark regions.
The color measuring device includes an elongated color measuring probe housing having a first end portion and a second end portion. A hollow cone shaped probe tip is attached to the first end portion of the probe housing. A target contact end of the probe tip is placed against a color target to be measured. Inside the first end portion of the probe housing is a battery powered white LED light source connected to a color measurement switch. When the measurement switch is actuated, the white light source illuminates the color target surrounded by the target contact end of the probe tip.
A light pipe is centered inside the first end portion of the probe housing and inside a portion of the probe tip. The light pipe captures the reflected light off the color target and projects the captured light onto a 3 color (RGB) sensor. The 3-color sensor collects a light signal, which is made up of percentages of red, green and blue. The percentages may be detected simultaneously or sequentially. An analog light signal is amplified and converter to a digital signal using an A/D converter. The A/D converter is part of a microprocessor mounted on a printed circuit board in the probe housing. The digital signal is transmitted from the microprocessor to a liquid crystal display, LCD, mounted in the second end of the probe housing. Also, the digital signal can be transmitted via a communications cable, such as a RS232 serial I/O port cable, an USB interface cable, or via an expansion slot of a pocket PC. The computer is used for storing data and displaying the color measurement on a display screen and comparing the measurement with similar color matches. Also, the computer allows for interfacing to the Internet, which provides downloading additional color lookup tables or transfer of color sample data.
These, and other objects of the present invention, will become apparent to those familiar with different types of color analyzers and devices used in measuring color when reviewing the following detailed description, showing novel construction, combination, and elements as herein described, and more particularly defined by the claims. It being understood that changes in the embodiments to the herein disclosed invention are meant to be included as coming within the scope of the claims, except insofar as they may be precluded by the prior art.